Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cao tuc » dao tuc, cao duc, cao suc
hieu va » lieu va, hieu qua
quan va » quan vi, quan ha, luan va
quan xa » quan ha, quan cua, quan tai
va cao » va cac, va co, va dao
tuc va » thuc va, truc va, tuc xa
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thu sach)) lien ((quan xa) OR (quan va)) hoi. hieu va cao tuc va hanh vi cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (thu sach)) lien ((quan xa) OR (quan va)) hoi. hieu va cao tuc va hanh vi cua vat~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thu sach)) lien ((quan xa) OR (quan va)) hoi. hieu va cao tuc va hanh vi cua vat*.